Information flow has increased substantially in recent years, and networks have evolved to accommodate not only a greater number of users but also higher data rates. An example of a relatively high speed network is the subject of ANSI/IEEE Standard 802.5 which provides a description of the peer-to-peer protocol procedures that are defined for the transfer of information and control between any pair of Data Link Layer service access points on a 4 Mbit/s Local Area Network with token ring access. At such data rates, however, wiring paths themselves become antennae that both broadcast and receive electromagnetic radiation. Signal coupling (crosstalk) between different pairs of wires is a source of interference that degrades the ability to process incoming signals. This is manifested quantitatively as decreased signal-to-noise ratio and, ultimately, as increased error rate. Accordingly, crosstalk becomes an increasingly significant concern in electrical equipment design as the frequency of interfering signals is increased.
Crosstalk occurs not only in the cables that carry the data signals over long distances, but also in the connectors that are used in cross-connect panels. ANSI/IEEE Standard 802.5 discloses a Medium Interface Connector having acceptable crosstalk rejection at the frequencies of interest. This Connector features four signal contacts with a ground contact, and is hermaphroditic in design so that two identical units will mate when oriented 180 degrees with respect to each other. This Connector is available as IBM Part No. 8310574 or as Anixter Part No. 075849. Crosstalk rejection appears to result from short connector paths, ground shields, and the selection of particular terminals for each wire-pair. As might be expected, such connector arrangements are relatively expensive and represent a departure from conventional interconnection hardware. For example, in commercial building applications, large bundles of wire-pairs terminate in electrical panels comprising linear arrays of individual connectors such as AT&T's 110-type insulation-displacement connectors (IDC). Each IDC accommodates a single wire pressed between its opposing contact fingers, and is so compact that many can fit into a small area. One bundle may come from a telephone central office while another bundle comes from telephone equipment within the building. Interconnecting particular wires from one bundle with particular wires from another bundle is accomplished with a patchcord comprising a cord with a plug (patch plug) attached to each end. The cord includes one or more wire-pairs within a plastic jacket. The patch plugs include a number of contact blades that are designed to be pressed into an equal number of IDCs within an array thereof. While the 110-type IDCs have become extremely popular because of their cost and size, the plugs used to make electrical connection with them suffer from excessive crosstalk at high frequencies. In particular, EIA/TIA Commercial Building Standards specify a maximum crosstalk at frequencies of 16-100 MHz. In order to meet end-to-end crosstalk requirements, the plugs themselves can only contribute a fraction of the total allowable crosstalk between wire-pairs.
Accordingly, it is desirable to design a patch plug having reduced crosstalk between conductor-pairs within the patch plug and between adjacent patch plugs.